Mechanical hammer



Sept. 13; 1932. OLL 1,877,462

MECHANI CAL HAMMYER Filed Jan. 13, 1931 2 ShGGtS-Sheet l ma I R. HOLLEMECHANICAL HAMMER Sept. 13, 1932,

Filed Jan. -15, 1931 2. Sheets-Sheet Patented Sept. 13, 1932 "UNITEDSTATES ROY HOLLEQOF CINCINNATI, OHIO MECHANICAL HAMMER The presentinvention relates to mechanical hammers of a mechanism whereby an impactmember which isunder the'influence of a suitably heavy compressionspring at all times may be lifted against the resistance of said springand liberated whereby the impact stroke is accomplished solely throughthe stored energy of the spring under compress1on. 1

Another object is to provide a mechanical hammer mechanism of this'typewhereby the movement just described is repeated with great rapidity andis initiated from a suit- M able rotary power source. f5 Another objectof the invention is to provide means whereby rotary motion from thepower source is translated into. smooth, rapld, reciprocation of thepiston member m" including the means to grip, raise and release an animpact member repeatedly and rapidly in its cycle ofmovement.

. These and other object are attained bythe means described herein anddisclosed inthe accompanying drawings, in which: c Fig. 1 is a sideelevational View of a device embodying the present invention and including power operating means therefor."

Fig. 2 is an end elevational view of a device of the invention, 3

@3 I Fig. 3 is a longitudinal cross sectional view of the device.

Fig. 4 is a view taken on line l l of Fig. 3.

Fig. 5 is a perspective view of the gripper H members formlng a detailof the nvention pact member from the grippingm'eans whereby the impactmember may deliver an impact stroke solely under the influence of thestored up spring energy. The reciprocation ofthe gripping membereffected through the intermed-ia ry of; a swash plate mechanism M-driven from. any suitable rotary sourceot power such as an electricmotor. Referring The present invention consists inthe pro-. vision of asuitably guided reclprocating 1m- Application filed January 13, 1931.Serial 'No. 508,416.

tothe drawings,the presentembodiment of the invention includes a housing8 provided with asuitable grip orhandle 9 opposite which is a-hollowcylinder 10. An impact member 11 has suitable bearing flanges 12 and 13which ride smoothly on the inner wall of the cylinder 10. A tapered head14 on the impact member 11 is undercut to provide a shoulder 15 uponwhich thehooks 16 of a pair of gripper members 17 may engage. Grippermembers 17 are mounted after the fashion of a pair of tongs upon a pin18 and are disposed between the arms 19 of a piston 20. A spring 21seated in a counterbore at "the rear of arms 19 rests in notches 22 atthe top of gripper member 17 whereby the hooks 16 are normally urged tothe position shown in Fig- The piston is. reciprocably mounted within asleeve 23'whichhas one end extending into the top of cylinder 10.Cylinder 10 is screw-threaded into a threaded bore 24 in the housing 8.The piston-'20 also has at its upper end apair of spaced arms 25' whichsupport a pin 26 that provides'a pivotalmounting for a finger 27 Atubular thimble 28 has a bore concentric with sleeve 23 and alsoprovides a bearing for the piston 20 during part of its movement. Thisthimble is seated in an enlarged bore interiorly of the housing 8 andforms an abutment for the top of a'heavy compression/spring 29.The'bottomend of the compression spring seats'upon. the bearing flange1-3 of the impact member 11so that the latter member is always urged to;the downward or outward limit of movement, The end of cylinder 10 has areduced.

hollow tool receiving portion 30 which provides an internalshoulder 31at its juncture with the remainderlof cylinder 1O.v =Whenthe bearingflangej 12 of impact. member ll is" seated on shoulder 31 the spring .29is under 20 and the gripper member 17 are at theirilowermost limitofreciprocation." It is to be observed then that only whenthe' shank 32of. a tool 33 is pressed against impact member 11. to move impactmemberill upwa rdlyagainst practically no compression'., In the positionshown in'Fi g. '3 itwill be noted that the piston spring'29 can'tliegripper hooks16 engage the shoulder 15 of the impact member.Forthis reason when the tool'is not held firmly into the hammer, themechanism will run idle. without effecting any reciprocation of theimpact member.

It will be observed that each otthe gripper members 17 is provided withan ear 35 which will engage the end 36 of thimble 28 as the pistonreaches its upward limit ofmovement; This effects a release or spreadingof the gripper members so that the hooks are disengaged from theshoulder on the head'14.- At the upper limit of movement of the impactmem- I ber 11 the spring 29 has been compressed to its utmost and, uponrelease of the hooks as stated the impact member is projected tosubstantially the opposite limit of its movement j whereit strikes-theend 32 of the tool shank with a maximum velocity.

' While-several different means may befemployedfor effecting thereciprocation of the piston 20, the preferred formherein'shownisemployed because it requires a minimum of power foroperation and furthermore because its operation is relatively smooth andqniet. The powersource may be an electric motor 37 having a suitableflexible drive shaft V j able switch contained in the handle 9- and I Iwill engage beneath the head as the piston gear 42 which is mounted onshaft 43. The

i V i "erat oiiitif thb' d v itie enclosed in'rtheusual tubular casing370 which I is connected at the hollowcoupling nipple 38 adjacent handle9. The electrical conductor; 39 'for the motor may be controlled-by asuitcontrolled by a trigger 40 (see Fig.1). Referring now to Fig.3, apinion 411 on;

avsu itable stud shaft, coupled to the flexible drive within thecoupling nipple 38, drives a latter is preferably journall ed vatopposite ends inball-bearings 44 and 45. Thepower translating mechanismis in the natureof a sswash plate device and consists of a pair ofconcentric members, namely, a rotating in ner member 46 and anoscillating outer member 47-. Member 46has the shaft 43 passing throughit on a center which is oblique tothe serge swaying ease-easy.and n? e ris iii-a awareness Q...-.i a 1n s for example ha lfea e ,gt g 1 Ara-fin.[11.2 O!. 4:H}--%J l4 1 {MEN 3 n e enema; a sane it. e i I w lealfanaeeig ail a n Wa no .iii iib iiifl ei i n we in the present Whenthe hammer is to be used the motor 1s connected to a suitable source ofelectrlc current (not shown) and remains at rest until the fingertrigger 40 is depresse Rotation of the flexible shaft inthe casing 37drives pinion 41 by direct coupling and this turns shaft 43. through theagency of gear 42.

fects a Wabbling movement which. is translat- .ed into rectilinearreciprocation of the piston QOby means of finger 27.

Considering now that the reciprocation of piston QOhas been initiated,the actual opera-v scribed. I 7 I p I Ifthe operator; nowinserts-thetool 33, for example a chisel or concrete cutting tool,m

tion of the 'impact inember will now be def the socket and holdsitlightly againstthe work with switch trigger, 40 depressed, the pistonwill be rapidly reciprocated but head. 14 of the impact member will notbe reached by the hooks 16. When the'operator presses the'hammer againstthe toolenoughf to slightly compressthe spring and bring the head 14within proper reach of the hooks, said l1ooks,.at the lower limit of thepiston stroke will be spread apartby the head and returns. The impactmember is now carried up by" the hooks and the spring 29 is placed undercompression. 'At about the upward limit of movement of the" piston,.1.e. at zero velocity of the piston, the-ears ofthehooks will have beendepressed against the end 36 of the thimbIeYQScausing an opening or.

spreading a aieor the hooks, whereupon the impactfmember 11 is violentlyprojected.

against the end 32 of the tool, ,thus'deliverin'g its work stroke. Thepiston-quickly follows thefree impact member on its downward strl .1. riifiiig lie ii tizs are Just 'appr eael mgfi ee at reineaeeasaiasueiiaran is tatement r, t liii. 1 salt in mph n n Eli-f "9iateeeaeefiatnaiite taste it 'tbaiametei nt ene qad'ileuaweltas estateamtels fiaettha h p l mbleisbemin mear 'l llgvl fi l ilg i z i'g'iiiiiii piiiii v iill$, ierenathaughi llz lfi'i i lt .9135?oifirelatiivelyisottsteelsimheseipaa tsihn le nfi mayabe*l-lardenddir'zhi i order; :to rprovidezprac-z 5ti'eallyqaniindefiniteiperindwogfi us''i lillhe oirlye j pantwhiiclninag aeqaire replacement inter-ta ls is thezinefipeas' g ii'aveagstrageriiiabout t centerswiien ffiny eeraptess tively holds thecylinder 10 in adjusted position.

What is claimed is:

1. In a portable mechanical hand hamme the combination with a suitablehousing, of a hollow cylinder communicating therewith, an impact memberhaving a shouldered head, said member reciprocable in the cylinder, a;coil spring normally urging the impact member to the end of thecylinder, a power driven shaft in the housing, a piston reciprocable inaxial alignment with the impact member,

means actuated by the shaft for reciprocating the piston, a pair ofgripping members yieldably urged to closed position and adapted to gripthe impact member, said gripping members being carried by the piston,whereby the impact member is pulled into the cylinder against theresistance of the coil spring, and means whereby the gripping membersare released from the impact member for subjecting the latter to theinfluence of the coil spring.

2. In combination with a hollow cylinder having a tool receiving socketat one end of a power reciprocated piston in the cylinder,

a pair of grippers pivoted together and carried by the piston,cooperating means on the.

grippers and cylinder for opening the grippers as the piston reaches oneend of its ath' of travel, spring 7 means disposed axlally within thepiston and yieldably resisting opening of the grippers, an impact memberslidable in the cylinder, and a coiled compression spring urging theimpact member toward the tool socket beyond the reach of the grippers.

3. In a portable mechanical power hammer the combination of a cylinder,a piston reciprocable therein, means to reciprocate the piston, a pairof gripper members pivoted together upon said piston, each of thegripper V members'having an ear intermediate its ends, a sleeve-likeprojection in the cylinder and surrounding the piston and spring meansseated axially within the piston and serving to yieldably retain thegripper members in a closed position, the ears on said gripper memberscooperating with the sleeve in the cylinder for effecting openingmovement of the gripper members against the axially acting spring means.I

In testimony whereof, I have hereunto subscribed my name this 10th dayof J anuary, 1931.

ROY I-IOLLE..

